PMMA material, preparation method and application thereof

Abstract

This invention provides a PMMA material, its preparation method, and its applications. By weight, the PMMA material comprises 71-99 parts PMMA resin, 5-30 parts a second polymer, and 0.1-1 parts a colorant. The second polymer comprises a styrene-nitrophenyl maleic anhydride-MMA terpolymer, wherein the molar percentage of nitrophenyl maleic anhydride structural units in the styrene-nitrophenyl maleic anhydride-MMA terpolymer is 31-48%; the molar ratio of styrene structural units to MMA structural units is (0.5-4.5):1; the colorant comprises solvent red and solvent green; the mass ratio of solvent red to solvent green is (2.9-6.5):1; and the total mass percentage of solvent red and solvent green in the colorant is ≥92%. In this invention, the PMMA material exhibits high infrared transmittance and good heat resistance.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a PMMA material, its preparation method, and its applications. Background Technology

[0002] Polymethyl methacrylate (PMMA) is a high molecular polymer formed by the polymerization of methyl methacrylate. Also known as "plexiglass", it has advantages such as no need for painting, high weather resistance, easy processing and molding, and low cost, and is widely used in automotive exterior panels and other fields.

[0003] Currently, with the rapid development of intelligent vehicles towards high automation and personalized interaction, in-vehicle B-pillar trim panels are upgrading from traditional decorative components to intelligent interactive terminals, and the demand for integrated biometric systems, such as facial recognition systems and palm vein recognition systems, is increasing daily. Infrared cameras, with their advantage of being unaffected by ambient light, have become a core component of B-pillar biometric systems—their near-infrared band can accurately capture 3D facial features. To meet this application, the B-pillar trim panel material needs to maintain structural strength while possessing high transmittance in a specific infrared band; therefore, higher requirements are placed on the performance of PMMA materials.

[0004] Furthermore, the methyl groups on the molecular chain of ordinary PMMA disrupt the spatial regularity of the molecular chain, resulting in a random structure and a non-crystalline material with poor heat resistance. This type of material often exhibits deformation and failure during high-temperature resistance tests (90℃ / 24h) on components. To improve the heat resistance of PMMA, a common method is to physically modify it by mixing heat-resistant agents with PMMA and then granulating the mixture. For example, adding a styrene-nitrophenyl maleic anhydride terpolymer to PMMA and then extruding and granulating it can improve heat resistance. However, the addition of the styrene-nitrophenyl maleic anhydride terpolymer is detrimental to improving infrared transmittance.

[0005] Therefore, developing a PMMA material with high infrared transmittance and good heat resistance is an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a PMMA material, its preparation method, and its applications. The PMMA material exhibits high infrared transmittance and good heat resistance, making it suitable for use in infrared-transmitting components or biometric systems.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a PMMA material, comprising, by weight, 71-99 parts PMMA resin, 5-30 parts a second polymer, and 0.1-1 parts a colorant; the second polymer comprises a styrene-nitrophenyl maleic anhydride-MMA terpolymer, wherein, by molar percentage, the nitrophenyl maleic anhydride-MMA terpolymer has a molar percentage content of 31-48% and a molar ratio of styrene structural units to MMA structural units of the styrene-nitrophenyl maleic anhydride-MMA terpolymer is (0.5-4.5):1; the colorant comprises solvent red and solvent green; the mass ratio of solvent red to solvent green is (2.9-6.5):1; and the total mass percentage content of solvent red and solvent green in the colorant is ≥92%.

[0008] In this invention, by adding a colorant composed of a styrene-nitrophenyl maleic anhydride-MMA terpolymer and solvent green and solvent red to PMMA resin, the infrared transmittance of PMMA material can be effectively improved while ensuring the good heat resistance of PMMA.

[0009] Secondly, by controlling the molar percentage of nitrogen-phenylmaleic acid imide structural units in the styrene-nitrogen-phenylmaleic acid imide-MMA terpolymer within a specific range, and simultaneously controlling the molar ratio of styrene structural units to MMA structural units within a specific range, it is beneficial to improve the infrared transmittance of the PMMA material while ensuring its good heat resistance. A higher molar percentage of nitrogen-phenylmaleic acid imide structural units results in lower infrared transmittance; a lower molar percentage results in poor heat resistance; and both a higher and lower molar ratio of styrene structural units to MMA structural units will affect the infrared transmittance.

[0010] Furthermore, by using a specific mass ratio of solvent red and solvent green to compound, the infrared transmittance of PMMA material can be effectively improved. If the proportion of solvent red or solvent green is too low or too high, the compounding effect will be poor, which will lead to a decrease in infrared transmittance. Moreover, the total mass content of solvent red and solvent green in the colorant is within a specific range, which is conducive to further improving the infrared transmittance.

[0011] In this invention, 71 to 99 parts of PMMA resin can be, for example, 72 parts, 74 parts, 76 parts, 78 parts, 80 parts, 82 parts, 84 parts, 86 parts, 88 parts, 90 parts, 92 parts, 94 parts, 96 parts, 98 parts, or any range of the above values.

[0012] In this invention, the PMMA material contains PMMA resin at a mass percentage of ≥60%, more preferably ≥70%, and particularly preferably ≥75%.

[0013] In this invention, the 5 to 30 parts of the second polymer can be, for example, 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, or any range of the above values.

[0014] In this invention, the mass percentage of the second polymer in the PMMA material is ≤30%, more preferably 6~25%.

[0015] In this invention, 0.1 to 1 part of colorant can be, for example, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts, 0.8 parts, 0.85 parts, 0.9 parts, 0.95 parts, or any range between the above values. In one embodiment, the mass percentage of colorant in the PMMA material is 0.2% to 1.0%.

[0016] In this invention, the molar percentage of nitrogen-phenyl maleic acid imide structural units in the styrene-nitrogen phenyl maleic acid imide-MMA terpolymer is 31-48%, for example, it can be 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47% or any of the above values, more preferably 32-38%.

[0017] The molar ratio of styrene structural units to MMA structural units in the styrene-nitrophenyl maleic anhydride-MMA terpolymer is (0.5~4.5):1, wherein the specific value in (0.5~4.5) can be, for example, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4 or any range of the above values, and more preferably (1~3):1.

[0018] In this invention, the molar percentage of each structural unit in the styrene-nitrophenyl maleic anhydride-MMA terpolymer is expressed as the percentage of each monomer in the total molar content of the monomers.

[0019] In this invention, the styrene-nitrophenyl maleic acid imide-MMA terpolymer can be obtained commercially or prepared using conventional methods.

[0020] Preferably, the density of the styrene-nitrophenyl maleic acid imide-MMA terpolymer is 1.1~1.3 g / cm³. 3 For example, it can be 1.12 g / cm³ 3 1.15 g / cm 3 1.18 g / cm 3 1.2 g / cm 3 1.22 g / cm 3 1.25 g / cm 3 1.28 g / cm 3 Or a range between any of the above values.

[0021] In this invention, the mass ratio of solvent red to solvent green is (2.9~6.5):1, wherein the specific value of (2.9~6.5) can be, for example, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, 5.8, 6, 6.2, 6.4 or any range of the above values, and more preferably (4.8~6.2):1.

[0022] In this invention, the total mass percentage of solvent red and solvent green in the colorant is ≥92%, for example, it can be 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100% or any of the above values, more preferably >98%.

[0023] In this invention, the solvent red content in the colorant is ≥80% by mass.

[0024] In this invention, the solvent red includes at least one of purine solvent dyes, azo solvent dyes, and anthraquinone solvent dyes; exemplary, it includes, but is not limited to, at least one of Solvent Red 179 and Solvent Red 195.

[0025] Preferably, the solvent green comprises anthraquinone solvent dyes; exemplary, it includes, but is not limited to, at least one of solvent green 3 and solvent green 28.

[0026] In this invention, the colorant may also contain solvent dyes of other colors as needed. For example, to obtain a black material, solvent yellow, solvent blue, solvent violet, etc., can be added and compounded. The mass percentage of other color solvent dyes in the colorant can be 0-8%.

[0027] In this invention, solvent red refers to red solvent dye, solvent green refers to green solvent dye; solvent yellow refers to yellow solvent dye, solvent blue refers to blue solvent dye, and solvent violet refers to violet solvent dye; wherein, solvent yellow, solvent blue, and solvent violet can all be selected from anthraquinone solvent dyes; for example, solvent yellow can be solvent yellow 114, solvent blue can be solvent blue 104, and solvent violet can be solvent violet 13.

[0028] Preferably, the density of the PMMA resin is 1.16~1.19 g / cm³. 3 For example, it could be 1.162 g / cm³. 3 1.165g / cm 3 1.168 g / cm 3 1.17 g / cm 3 1.172 g / cm 3 1.175 g / cm 3 1.178 g / cm 3 1.18 g / cm 3 1.182 g / cm 3 1.185 g / cm 3 1.188 g / cm 3 Or a range between any of the above values.

[0029] Preferably, the melt index of the PMMA resin at 230°C and 3.8 kg load is 2~10 g / 10 min, for example, it can be 2.5 g / 10 min, 3 g / 10 min, 3.5 g / 10 min, 4 g / 10 min, 4.5 g / 10 min, 5 g / 10 min, 5.5 g / 10 min, 6 g / 10 min, 6.5 g / 10 min, 7 g / 10 min, 7.5 g / 10 min, 8 g / 10 min, 8.5 g / 10 min, 9 g / 10 min, 9.5 g / 10 min or any range between the above values.

[0030] In this invention, the term "melt index" is also known as "melt flow rate", abbreviated as "MFR", and the unit is g / 10 min. The MFR in this invention can be tested using the method in ISO 1133-1-2011.

[0031] Preferably, the PMMA material further includes 0.1 to 10 parts by weight of a second additive, for example, 0.2 parts, 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or any range of the above values.

[0032] Preferably, the second additive includes at least one of an antioxidant, a lubricant, and a light stabilizer.

[0033] In this invention, the antioxidant includes any one or a combination of at least two of hindered phenolic antioxidants, hindered amine antioxidants, phosphite antioxidants, and thioether antioxidants. The light stabilizer includes any one or a combination of at least two of benzotriazole light stabilizers, triazine light stabilizers, benzophenone light stabilizers, salicylate light stabilizers, and hindered amine light stabilizers. The lubricant includes any one or a combination of at least two of silicone lubricants, vinyl polymer lubricants, and ester lubricants.

[0034] Preferably, the PMMA material further comprises 0.1 to 2 parts by weight of antioxidant, 0.1 to 1 part by weight of lubricant and 0.1 to 2 parts by weight of light stabilizer.

[0035] Preferably, the heat distortion temperature of the PMMA material is ≥75℃.

[0036] Preferably, the infrared transmittance of the PMMA material is ≥78%.

[0037] In a second aspect, the present invention provides a method for preparing the PMMA material described in the first aspect, the method comprising the following steps: The PMMA resin, second polymer, colorant, and optional second additive are mixed and extruded to obtain the PMMA material.

[0038] Preferably, the extrusion temperature is 80~270℃.

[0039] In this invention, the extrusion speed is 200~400 rpm, and the screw diameter used for extrusion is 38~55:1.

[0040] Thirdly, the present invention provides an application of the PMMA material described in the first aspect in infrared-transmitting components or biometric systems.

[0041] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows: The PMMA material provided by this invention uses a styrene-nitrophenyl maleic anhydride-MMA terpolymer with a specific structure and a colorant with a specific composition, which is beneficial to improving the infrared transmittance of the PMMA material while ensuring its good heat resistance. Detailed Implementation

[0043] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0044] All materials used in this invention are commercially available or prepared using conventional methods; unless otherwise specified, the materials used in this invention are as follows: PMMA resin PMMA-1: PMMA 8N, ROHM Chemicals; melt index is 3g / 10min (230℃ / 3.8kg).

[0045] PMMA-2: PMMA 80NHX purchased from Asahi Kasei; melt index is 5.5 g / 10 min (230℃ / 3.8 kg).

[0046] Second polymer (St-PMI-MMA) The specific types are shown in Table A.

[0047] Table A In this invention, the styrene-nitrophenyl maleic acid imide-MMA terpolymer is prepared in-house. Taking St-PMI-MMA-1 as an example, the specific preparation method includes: Under nitrogen protection, methyl methacrylate (MMA) and N-phenylmaleimide (PMI) were mixed at 70°C for 30 min. Then, azobisisobutyronitrile (DIBN) and tert-dodecyl mercaptan (TDM) were added, followed by the dropwise addition of styrene (St). After the dropwise addition was complete, BIBN and TDM were added again, and then an aqueous solution of hydroxyethyl cellulose (1 g / L) was added to make the system a suspension emulsion. The reaction was continued for 2 hours, and then the temperature was raised to 95°C and held for 1.5 h. The reaction was then stopped. The resulting polymer was distilled, washed, and dried to obtain the styrene-N-phenylmaleimide-MMA terpolymer. Based on a total monomer molar content of 100%, the molar contents of methyl methacrylate, N-phenylmaleimide, and styrene are 30%, 36.8%, and 33.2%, respectively; the total mass of azobisisobutyronitrile is 3% of the total monomer mass; the mass of the azobisisobutyronitrile added for the first time accounts for 45% of its total mass; the total mass of tert-dodecyl mercaptan accounts for 2% of the total monomer mass, and the mass of the tert-dodecyl mercaptan added for the first time accounts for 45% of its total mass.

[0048] The difference between St-PMI-MMA-2~St-PMI-MMA-7, St-PMI-MMA-d1~St-PMI-MMA-d4 and St-PMI-MMA-1 is that the monomer content can be adjusted according to the structural composition in Table A.

[0049] Styrene-nitrophenyl maleic anhydride terpolymer (denoted as PMS): The difference between PMS and St-PMI-MMA-1 is that in the preparation method, MMA is replaced with an equimolar amount of maleic anhydride, while the other preparation methods are the same as those for St-PMI-MMA-1.

[0050] Colorant (denoted as Z) In this invention, the colorant is obtained by uniformly mixing solvent red, solvent green and optionally solvent yellow. The formulation of the colorant by weight is shown in Table B.

[0051] Among them, Solvent Red 179: 14H-benzo[4,5]isoquinoline[2,1-a]piperidin-14-one is commercially available.

[0052] Solvent Red 195: 4-[(4-aminophenyl)azo]-3-methyl-N-(2-methylphenyl)benzenesulfonamide, commercially available.

[0053] Solvent Green 3: 1,4-di-p-tolueneaminoanthraquinone, commercially available.

[0054] Solvent Green 28: 1,4-Di[[4-(1,1-dimethylethyl)phenyl]amino]-5,8-dihydroxyanthraquinone, commercially available.

[0055] Solvent Yellow 114: 2-(3-hydroxy-2-quinolinyl)indan-1,3-dione, commercially available.

[0056] Table B Antioxidant: Hindered phenolic antioxidant, IRGANOX 245, BASF.

[0057] Light stabilizer: HALS-type light stabilizer, TINUVIN 770DF, BASF.

[0058] Lubricant: Pentaerythritol stearate.

[0059] Examples 1-15, Comparative Examples 1-12 Examples 1-15 and Comparative Examples 1-12 each provide a PMMA material, and the formulations of the PMMA materials are shown in Tables 1-3 by weight.

[0060] The preparation method of the PMMA material includes the following steps: (1) According to the formula amount, PMMA resin, second polymer, colorant and optional antioxidant, light stabilizer and lubricant are placed in a high-speed mixer and mixed evenly to obtain a premix; (2) The premix obtained in step (1) is added to a twin-screw extruder. The screw speed of the twin-screw extruder is 350 rpm, the length-to-diameter ratio is 55:1, the temperatures of zones 1-9 are 90℃, 120℃, 200℃, 240℃, 250℃, 255℃, 255℃, 250℃, and 250℃, respectively, and the die head temperature is 250℃. After melt mixing and extrusion granulation, the PMMA material is obtained.

[0061] Performance testing Heat distortion temperature: tested according to ISO 75-2-2004, with a load of 1.8 MPa; Infrared transmittance: PMMA material was injection molded at a temperature of 200℃ to form a sample with a thickness of 2mm; the infrared transmittance of the sample was tested using an LS108A lens transmittance tester with an infrared wavelength of 850nm.

[0062] The specific test results are shown in Table 1-3.

[0063] Table 1 Table 2 Table 3 As shown in Tables 1-3, the PMMA material provided by the present invention is a terpolymer of styrene-nitrophenyl maleic anhydride-MMA with a specific structure and a colorant with a specific composition. The resulting PMMA material has high infrared transmittance and heat distortion temperature; the heat distortion temperature of the PMMA material is ≥75℃ and the infrared transmittance is ≥78%.

[0064] As can be seen from Example 1 and Comparative Example 1, when the styrene-nitrophenyl maleic acid imide-MMA terpolymer is replaced with the styrene-nitrophenyl maleic acid imide-maleic anhydride terpolymer, the infrared transmittance of the material decreases.

[0065] As can be seen from Example 1 and Comparative Examples 2-4, the content of nitrogen-phenyl maleic acid imide structural units in the styrene-nitrogen phenyl maleic acid imide-MMA terpolymer is low, resulting in poor heat resistance; when the content is high, the infrared transmittance decreases; when the ratio of styrene structural units to MMA structural units is not within a specific range, the infrared transmittance decreases.

[0066] As can be seen from Examples 1 and Comparative Examples 6-11, the infrared transmittance of PMMA materials is reduced when solvent red and solvent green are not mixed in a specific ratio.

[0067] As can be seen from Example 1 and Comparative Example 12, the total mass percentage of solvent red and solvent green in the colorant is low, resulting in a decrease in the infrared transmittance of the obtained PMMA material.

[0068] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A PMMA material, characterized in that, The PMMA material comprises, by weight, 71-99 parts PMMA resin, 5-30 parts second polymer and 0.1-1 parts colorant; The second polymer comprises a styrene-nitrophenyl maleic acid imide-MMA terpolymer; The molar percentage of nitrogen-phenyl maleic acid imide structural units in the styrene-nitrogenous maleic acid imide-MMA terpolymer is 31-48%. The molar ratio of styrene structural units to MMA structural units in the styrene-nitrophenyl maleic anhydride-MMA terpolymer is (0.5~4.5):1; The colorants include solvent red and solvent green; The mass ratio of solvent red to solvent green is (2.9~6.5):1; The total mass percentage of solvent red and solvent green in the colorant is ≥92%.

2. The PMMA material according to claim 1, characterized in that, The molar percentage of nitrogen-phenyl maleic acid imide structural units in the styrene-nitrogenous maleic acid imide-MMA terpolymer is 32-38%. Preferably, the molar ratio of styrene structural units to MMA structural units in the styrene-nitrophenyl maleic acid imide-MMA terpolymer is (1~3):1; Preferably, the density of the styrene-nitrophenyl maleic acid imide-MMA terpolymer is 1.1~1.3 g / cm³. 3 .

3. The PMMA material according to claim 1 or 2, characterized in that, The mass ratio of solvent red to solvent green is (4.8~6.2):1; Preferably, the total mass percentage of solvent red and solvent green in the colorant is >98%.

4. The PMMA material according to any one of claims 1 to 3, characterized in that, The solvent red includes at least one of purinone solvent dyes, azo solvent dyes, and anthraquinone solvent dyes; Preferably, the solvent green comprises anthraquinone solvent dyes.

5. The PMMA material according to any one of claims 1 to 4, characterized in that, The PMMA resin has a melt index of 2~10g / 10min under conditions of 230℃ and 3.8kg load.

6. The PMMA material according to any one of claims 1 to 5, characterized in that, The PMMA material further includes 0.1 to 10 parts by weight of a second additive; Preferably, the second additive includes at least one of an antioxidant, a lubricant, and a light stabilizer.

7. The PMMA material according to any one of claims 1 to 6, characterized in that, The PMMA material further includes, by weight, 0.1 to 2 parts antioxidant, 0.1 to 1 part lubricant and 0.1 to 2 parts light stabilizer.

8. The PMMA material according to any one of claims 1 to 7, characterized in that, The infrared transmittance of the PMMA material is ≥78%.

9. A method for preparing PMMA material according to any one of claims 1 to 8, characterized in that, The preparation method includes the following steps: The PMMA resin, the second polymer, the colorant, and the optional second auxiliary agent are mixed and extruded to obtain the PMMA material.

10. The application of the PMMA material according to any one of claims 1 to 8 in an infrared-transmitting component or a biometric system.

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